Andrew oratk



(No Model.)

A. ORA-1K.

BALANUBD VALVE.

No. 334,690. Patented Jan. 19, 1886.

V j I 3 v42 771) enior:

.Anafiew Grail,

'W iesses i UNITED STATES PATENT OFFICE.

ANDREWCRAIK, OF WILLIAMSPORT, PENNSYLVANIA, ASSIGNOR TO RILEY & MELHUISH, OF SAME PLACE.

BALANCED VALVE.

.-PECIPICATION forming part of Letters Patent No. 334,690, dated January 19, 1886.

Application filed May 1], 1885.

To all whom it may concern;

Be it known that I, ANDREW CRAIK, of Williamsport, in the county ofLycoming and State of Pennsylvania, have invented certain new and useful Improvements in Balanced Valves, of which the following is a specification.

My invention relates to steam-engines, and particularly to a novel form of balanced slide and cut-off valves, hereinafter fully set forth, together with other features and details.

In the drawings accompanying this description, Figure 1 is a top plan view of the cylinder and steamehest; Fig. 2, a longitudinal central sectionon the line 0050, Fig. 3; Fig. 3, a transverse section on the line y y of Fig. 1; Fig. 4, a perspective view of the slide-valve and cut-off valve together removed from the valve-chest; Fig. 5, a perspective view of the cut-0E valve alone; Figs. .6 and 7 ,views showing the valves in different adjustments.

A indicates the cylinder; B, the piston; G, the steam-chest; D, the main slide-valve, and E the cut-off valve.

As best shown in Fig. 4, the valve D is of rectangular form in cross-section,and as shown in Figs. 2 and 3 it is set with one of its diagonal axes radial to the axis of the cylinder; or, in other words, instead of presenting a single flat face to its seat it presents a V-shaped face or two faces at an angle to each other, the valve-seat a being fashioned to correspond.

' The end portions of thevalve D are of a size to fill the valve-chest, the upper side of which is formed by V-shaped cap-plates F and G, placed outside of the valve and bolted to the chest, wit-h a space, b, between them from end to end, the inner plate, F, being shorter than the interior of the chest, to permit steam to enter space I) at both ends of the chest. The middle portion of the valve D is reduced in size, but is of the same form as the ends, the reduction being made for the purpose of affording space for the cutoff valve E, which, as shown best in Fig. 5, is of V form in crosssection, and as' shown in Figs. 3 and 4. is of the same proportions as the end sections of valve D, so that when placed upon the reduced middle portion thereof, as in Figs. 4 and 5, its faces shall be flush with those of the valve. The cut-off valve is shorter than the reduced portion of valve D, and has a longi- Serial No. 165,072. (No morlcl.)

tudinal movement thereon, the spaces between the ends of the cut-off valve and the enlarged heads or ends forming the steam-passages by which steam finds its way to the supply ports of the cylinder, as presently explained.

H indicates a steam supply or inlet pipe through which steam is brought to the valvechest, said pipe or inlet being divided into two branches, 0 c, by a bridge, d, as shown in Fig. 2. Outside of the branches 0 c of the inletpipe H are ports I I, through which steam enters and escapes from the cylinder A. The openings or ports 0 c and the ports I I open into the valve'chest at such relative points that when the valve D moves entirely-clear of either port I, as in Fig. 2, one of its enlarged heads covers the port a nearest said port I, while the other ports a and I are placed in communication, unless closed by the cutoff valve E. The play of valve E is such as to afford a space between its ends and the heads or enlarged portions of the valve D, alternately at opposite ends of valve E, sufliciently wide to connect the ports 0 and I at that end where the space occurs, as will be understood upon referring to Fig. 6. The steam entering through ports 0 0 passes entirely around the reduced middle portion of valve D, and consequently exerts alike pressure upon all sides, thereby perfectly balancing the valve. The valve D is made hollow and open from end to end, so that steam escaping from the cylinder through the ports I I into the steam-chest enters the interior of the valve, and pressing equally in all directions likewise balances the valve. The enlarged heads or ends of valve D form barriers or separating-walls between the live-steam and the exhaust-steam spaces. The slide-valve D is moved by an eccentric 9o rigidly'secured to the shaft, as in ordinary slide-valve engines, and the cut-oh valve E is moved by a shifting eccentric controlled by centrifugal weights, as is the case in various engines-an arrangement which causes the two 93 eccentrics to maintain a fixed relation to each other, but causes the throw of the cut-off eccentric to vary according to the speed of the engine, and thus to vary the throw of the cutoff valve. 7 t

To reduce the bearing-surface of the capplate F, itis formed with raised ribs 0, which IOC bear upon the enlarged heads or ends of valve D, as shown in Fig. 2. This construction permits the oil and the slight amount of water due to condensation of the steam to accumulate in the spaces between the ribs, and thus to lubricate the wearing-faces more perfectly than could otherwise be done, and also serve as a packing to prevent the steam from working between the faces. This method of packing is well known and frequently used for pistons and like parts.

To compensate for wear of the valve or seat, the cap-plate F may be set down by tightening the screws or bolts which hold it in place; or a separate bearing-block, J, may be provided to rest upon the reduced portion of the valve, as indicated in Fig. 2. Beneath the plate F is a layer of suitable packing material, and by turning the screws or bolts by which the plate F is held in place the packing is compressed and the plate allowed to hear more upon the valve,and thereby compensate for wear. Should it be desired to adjust the valve without removing the plate F, the setscrews connecting the block J and plate F (shown in Fig. 3) maybe turned,and the valve thereby adjusted. Steam escaping into the valve-chest passes through the ports I I, passes through the ports or outlets 9 into space 2) between plates F and G, and escapes through outlet K. The parts being thus constructed, steam enters by pipe H, passes into space It between the valves D E, and by said space to the port I, beneath the reduced portion of valve D, while steam exhausts from the opposite end of the cylinder through the port I, from which the valve is at that time wholly removed, and passes through outlets g and space b to exhaust K. At the proper point in the stroke-a point regulated by the setting of the eccentrics in the first instance, and the shifting of the cutoff eccentric under varying speeds of the enginethe cutoff valve is caused to move and close the space h, through which steam is entering the cylinder.

In Fig. 2 the cutting off is represented as occurring at one-third of the stroke. The cutoff valve E is provided with a lug, i, which works in a slot, j, in the valve D, the lug extending into the interior of valve D, where it connects with the rod L, by which the slidevalve is connected with the eccentric.

The automaticallyshifting eccentric being a common mechanical contrivance for the purpose herein set forth, it is not deemed necessary to represent it here, its purposes,'functions, and mode of operation being wholly unchanged in its use in this connection. It will be seen that in case of wear, merely setting up the cap-plate or its bearing-block takes up the wear on all the faces at once; and it will also be observed that the valve is at all times perfectly balanced. The valve D has a bearingsurface at each end and one at the middle, the latter formed by the cutoff valve E and block J, as shown in Figs. 2, 6, and 7.

Having thus described my invention, what I claim is- 1. In a steam-engine, the combination of a steam-valve having four faces, and set with its diagonal axis radial to the cylinder, and a V- shaped cut 01f valve seated upon a reduced portion of said steam-valve, substantially as shown.

2. In a steam-engine, the combination of a steam-chest having a V-shapcd valve-seat, a slide-valve having four faces, two adapted to fit said seat, a V-shaped cap-plate fitting the other two faces of the valve, and a V-shaped cut-off valve applied to the slide-valve, substantially as shown.

3. In combination with cylinder A and steam-chest C, slide-valve D, having enlarged ends and reduced middle portion, and cut-off valve E, applied to said reduced portion, substantially as shown.

4. The combination, substantially as shown, of cylinder A, steam-chest C, hollow rectangular valve D, open at both ends, and V- shaped cutoff valve E, mounted upon the reduced central portion of valve D, substantially as described and shown.

5. In combination with cylinder A, steamchest 0. ports I I, and steam-inlet H, steamvalve D, having reduced middle portion and enlarged ends, cut-oft valve E, seated upon the reduced portion of valve D,and caps F G, all combined and arranged to operate substantially as described and shown.

6. In combination with cylinder A and valve-chest O, steam-valve D, having reduced middle portion provided with slotj, and cutoft' valve E, provided with lug i and rod L.

7. In a steamengine, the combination of a cylinder, a valve-chest, suitable inlet and outlet ports, a slide-valve having bearing-faces at each end and reduced between the said faces, and an independent bearing-block bearing upon said reduced portion, as shown.

ANDREWV CRAIK.

\Vitnesses:

W. P. RILEY, O. LARUE MUNsoN. 

